The auditors reviewed provider directories for three health plans — Anthem Blue Cross in Fresno County, Health Net in Los Angeles County, and Partnership HealthPlan of California (Partnership HealthPlan) in Solano County. Some of the doctors listed had incorrect telephone numbers, and others were no longer participating in the health plan.

The three health plans contained inaccurate information for 3 to 23 percent of providers, depending on the plan, the report says.

Health Care Services failed to catch any of the errors, the audit says.

The audit also found that the agency hasn’t properly conducted annual medical audits to ensure the plans are meeting the medical needs of enrollees. Health Care Services did not perform any annual medical audits before 2012 and performed medical audits on less than half of the health plans in fiscal year 2013–14.

Meanwhile, the office that handles complaints from Medi-Cal members has a telephone system that can’t handle the volume of calls it receives and there aren’t enough staff members to answer all the calls the system does except, the audit found.

Ombudsman office data show that the telephone system rejected from about 7,000 to more than 45,000 calls per month between February 2014 and January 2015. And the office has only been able to answer 30 to 50 percent of the calls the phone system has accepted, with an average of 12,500 calls going unanswered each month between February 2014 and January 2015.

The agency is working to upgrade its phone system, according to the audit.

Health Care Services agrees with many of the state auditor’s recommendations, director Jennifer Kent said in a release.

“DHCS ensures that Medi-Cal managed care health plans are meeting the important physician to member ratios required by law,” she said. “We do so through the various tools in our comprehensive monitoring and oversight program.”

Among the audit’s recommendations is that the agency create a process to ensure the adequacy of provider networks and directories by September.